The issue, which is still the main political debate over REACH, has pitted the Parliament's environment committee and the UK presidency against the industrial and internal market committees, backed by the European Commission.

The former are pushing for more stringent testing to be carried out by companies importing or producing chemicals, while the latter want to relieve the burden on industry under a 'risk- based' approach, offering a waiver for further tests if a company says that the risk is limited.

A similar divide has appeared over the authorisation of chemicals. Under the text backed by Parliament's environment committee, companies will have to substitute chemicals where alternatives are available and cost-effective. In addition, they will have to renew their authorisation every five years.

The Commission and the pro-industry committees in Parliament would allow companies to avoid substituting the chemical in question if they could prove that it was adequately controlled.

But the final positions are likely to become clearer in the coming weeks, starting with the gathering of ministers in Luxembourg on Tuesday.

In recent working groups in the Council of Ministers, several member states - including Italy, Ireland, Poland and Greece - have opposed the UK presidency of the EU's strict registration rules.

Greece and Poland are even pushing for the risk-based approach to be applied to chemicals imported in larger tonnes, a position that would be supported by industry.

"We would certainly want to see the risk-based approach applied to chemicals imported in the 1-10 tonne range to make the project workable for small businesses," said a spokesperson at business association UNICE. "If it was extended to the 100 tonne range that would be even better."

A campaigner at World Wide Fund for Nature (WWF) said: "International standards say that 23 tests are needed to do a basic substance evaluation. What the internal market and industry committees have proposed makes REACH entirely worthless."

The November plenary session in Strasbourg may also surprise observers expecting a repeat of the vote in the environment committee this week. In the first place, all the amendments from the internal market committee will go straight to plenary which - unless compromises are reached in the meantime - would see MEPs voting on separate blocks of amendments.

The final text also depends on which way the liberals swing on the day. "In the environment committee the liberals were really deciding the majority vote," said one observer. Centre right EPP-ED members, many of whom failed to vote in committee, could also be persuaded to move ahead of the plenary vote on 15 November.